ENDOTHELIAL CELLS

Part 3 of the journey.

The key to controlling the health of your heart is nitric oxide.

Remember what we said above, if there is one thing to gain from reading this section is to understand the role of the endothelial cells.

Within the intima layer of the artery is a lining so thin (about one cell thick) that can not be seen by the naked eye. This layer is called the endothelium.

Healthy endothelial cells produce nitric oxide, an important signaling molecule that helps keep arteries supple.

What does this mean?

Before we look at this, Dr Ignarro and colleagues won the Noble Prize for Medicine in 1998 for this discovery.

1. When nitric oxide enters a cell, it stimulates a biochemical process that relaxes and dilates blood vessels.

2. Nitric oxide also helps keep atherosclerosis in check by preventing platelets and white blood cells from sticking to the blood vessel walls.

3. The molecule also slows the abnormal growth of vascular muscle which can thicken blood vessel walls.

“Endothelial cells are the prima donnas within blood vessels. They control almost every activity that occurs in the vessels and they are fundamentally altered with age.” Dr Lakatta “People who maintain a healthy endothelium as they get older and those who make an effort to do things that promote the repair of injured endothelium can reduce the risk of heart attacks and strokes caused by atherosclerosis or hypertension”.

Unhealthy endothelial cells are a different story. In these cells, nitric oxide regulation is impaired and can not function properly. To make nitric oxide, endothelial cells need L-arginine, an amino acid that is one of the basic building blocks of proteins. Normally, endothelial cells have plenty of L-arginine. In fact, some researchers consider the decreased availability of nitric oxide in the endothelium as one of the earliest signs of arterial ageing and a pathological sign of atherosclerosis and high blood pressure.

As we close the end of the journey through the arteries, we can see that our arteries develop a layer of plaque which then accelerates during our 50’s and 60’s as the endothelial cells can no longer produce nitric oxide.